DC motors of the permanent magnet type are presently utilized in automobiles for implementing the power assist function for vehicle seats, windows and door locks. In some vehicles ten or more of these permanent magnet motors may be employed. In conventional systems each motor requires two power switches, such as relays, in order for each motor to be operated independently of the other. Thus, in a system comprising ten motors, a total of twenty such relays would be required. Considerable savings in both cost, weight and space can be achieved by reducing the number of power switches required if certain limitations in terms of simultaneous motor operation are acceptable.